Gwen makes a video recording of the last events accompanying the end of the world.
Prime Minister Brian Green informs the nation that they're opening the schools so parents can send their children there. Government representatives will visit and discuss inoculations. Rhiannon and Johnny watch and inform their children they won't be going, thanks to Ianto's warning. She tells her son to run to the neighbor houses and pass on the message that the schools aren't safe.
Anna Frobisher tells her daughters they won't be going to school.
At the Prime Minister's offices, General Pierce tells Bridget Spears that he'll be handling the matter from now on, on behalf of the UN, given their demonstrated incompetence. He orders Bridget to report to him and she briefs him on the 2,600 primary schools where soldiers will arrive and transport the children. When Green notes that the soldiers might mutiny, Pierce tells them that the soldiers have been informed if they refuse to do their duty, their families will be held liable.
Colonel Oduya of UNIT goes to the 13th floor where Dekker is waiting, having survived the infection. Oduya addresses the 456 and informs them that they're initiating the plan. However, he asks how the 456 will be picking up the children once they're assembled. The 456 direct his attention to a monitor, which shows the pillar of light that accompanied their initial arrival. Oduya then asks as a father why they need the children. The 456 says the children are for "the hit." They create chemicals that give the 456 pleasure. When Green, watching on the monitor, recoils in horror, Pierce reminds him that Britain began the trade. He then has no choice but to order the troops to move into position.
Many children return to school while the government asks for the people's trust.
Frobisher and Bridget go to see Gwen and Jack at the school where the corpses from the MI5 building are being kept. Gwen notes that the threat still stands and they'll release the information. Frobisher insists that they're at a tipping point and if she wants to tip it into Hell a little earlier, he invites her to go ahead. Jack admits that Frobisher is right and indicates the bodies. He tells Gwen to call Rhys and tell him that they've lost. Rhys is sitting in a park when he gets Gwen's call. She tells him it's too late and they've killed Clem and Ianto. Meanwhile, Frobisher tells Jack that Lois is under arrest for espionage, but Steven and Alice have been released. Jack asks if Ianto's sister has been told but Frobisher says the names haven't been released yet. He asks if Gwen can tell Rhiannon to grant one moment of grace.. and because he can't look at Gwen any more. Frobisher agrees and sends Gwen and Rhys via helicopter to Rhiannon's home. The soldiers then arrest Jack and take him away.
Jack is locked in a cell next to Lois. She asks for answers about what's going on but Jack ignores her when she wonders what to do.
At Ashtown Down, Johnson release Alice and Steven and takes them to the monitor room. She shows Alice the image they took of a child hooked up within the containment chamber and explains it was one of the children abducted in 1965. Johnson warns Alice that the government will be handing millions more over in two hours' time.
Green summons Frobisher to his office and informs him that his name was chosen and his children will be "inoculated." The news media will be sent to Frobisher's house to publicize the event. When Frobisher points out there is no inoculation, Green insists it will reassure the public, and then his children will be taken to one of the rendezvous points. He wants to make sure that the government is also seen as victims of the 456. When Frobisher warns that he'll tell people the truth if he's put on camera, Green is unconcerned. Frobisher protests but all Green can do is apologize and then dismiss him.
Frobisher goes to Bridget and asks for a Requisition 34 but refuses to tell her what it's for. She goes to get it and brings a metal case back to him. Frobisher takes it, kisses her on the cheek, and leaves.
Gwen and Rhys arrive in Cardiff where PC Andy is waiting to welcome them back. He drives them to the house and demands answers, but Gwen refuses to explain anything. Rhys says that she's pregnant and Gwen admits that Torchwood ruined her life, negating the Pill with all of its retcons and chemical treatments. Rhys wonders how it was ruined and Gwen asks if he wants to have children in a world like theirs. When he insists she's not getting rid of it, Gwen says they'll see.
With an hour left, the troops move into position. As Frobisher drives home, Bridget goes to see Lois in her cell. She tells her how she met John Frobisher. It was 30 years ago, before Lois was born. She met Frobisher and thought to keep an eye on him even though he didn't seem to have much future. Frobisher stayed the course and kept working all of his life. Ten years later, she came to work for him after Frobisher asked for her by name. Bridget admits Frobisher wasn't perfect but he always worked hard. She wants to make sure that Lois knows that Frobisher was a good man and whatever happened wasn't his fault. She then goes back to work.
At home, Frobisher sends his children upstairs and kisses his wife. As she goes upstairs, he takes a revolver out of the case, goes upstairs, and kills his daughters, his wife, and then himself.
Gwen has Rhys wait at the car while she goes inside with PC Andy to find out where Rhiannon's two children are. Gwen says they need to get the children away and asks him to trust her. Rhiannon answers the door and explains that she's keeping all the neighbor children there. They go in and find the house filled with children. Gwen remembers Jack's last words to her, to save Ianto's niece and nephew.
The time arrives and Pierce gives the orders to the military to mobilise. They start taking away the children over the objections of teachers and parents.
Gwen breaks the news of Ianto's death to Rhiannon and Johnny. They tell her to get out but she tries to share what she knew about Ianto. However, when Rhiannon realizes that Gwen didn't know the truth about Ianto's father, she insists that Gwen didn't know her teammate at all.
Alice watches Steven play with some soldiers. Johnson comes over and offers her some coffee, and warns that the operation has begun.
Pierce gets word that many of the children in the target area are staying at home. He orders the troops to mobilise.
Rhys sees the soldiers arrive down the road. He runs inside, where Gwen vows that they have to get the children away. She tells them that Ianto died trying to stop the government and warns that Rhiannon and Johnny will never see their children again.
Johnson tells Alice that Steven will be safe as one of the "nice kids." The government is only getting rid of the 10% of the lower classes. Alice isn't consoled and Johnson insists that she protects the state, and was brought up to protect the state. Alice wonders what the world will be like to the remaining 90%, and says the one person she needs if she wants to protect the state is Jack Harkness.
Soldiers break into the holding facility and release Jack. Lois pounds on the door in frustration but can only watch as he's taken away to the roof and escorted to a helicopter.
Dekker discovers soldiers taking his records. When he intervenes, they knock him out.
Rhys, Gwen, Rhiannon, and Johnny get the children ready to go while PC Andy tries and fails to contact police headquarters. The soldiers break in the front and Johnny goes back to try and stop them. He hugs Rhiannon briefly and insists that someone has to stop them. Gwen leads the others out the back while Johnny organises the neighbors to fight back. PC Andy watches for a moment, sees more children being taken away, and then takes off his uniform and fights the soldiers. The neighbors and Andy are soon smashed to the ground while Gwen and Rhys get the children to a nearby series of abandoned buildings and tells them to be as quiet as they can.
As Dekker is escorted in, Jack is brought in and Steven and Alice see him. Steven is taken away for safety while Dekker is taken into a room. Johnson tells him that he needs to find the 456 wavelength so they can fight back. Dekker warns that it's a waste of time and Johnson shoots him in the leg. She then turns to Jack and asks if Alice was right about how good he was. Jack smiles and goes to work, accessing the Torchwood software. Dekker says he hacked into Torchwood years ago and there's nothing. Alice picks up a signal from a pirate station that shows the military taking away the children to the rendezvous spots.
Gwen records her video statement and Rhys asks if she intended to get rid of their child. Gwen assures her that she would never do that and apologizes.
Pierce orders his men to shut down the pirate station and is informed that the people are starting to fight back. They only have 80% of the designated children. Oduya informs the 456 of the limited numbers and asks if it's sufficient but the 456 demand 100%. Pierce authorises maximum force. As Bridget continues her work, Denise says she doesn't have to be there but Bridget insists that Frobisher would have wanted it that way. She watches Green intently.
Jack tries to program a constructive wave to feed back into the 456. Dekker warns that it wouldn't have any greater effect than shouting. Jack wonders why Clem died and how the 456 did it. Johnson plays back the recording while Jack realizes that the connection between Clem and the 456 somehow hurt them. Dekker identifies the recording as something new.
The soldiers step up their efforts to assemble all of the children. Meanwhile, Jack duplicates the new frequency and Dekker suggests they can transmit it the same way the 456 does. Jack refuses to listen but Dekker explains that they'll need a child to act as the centre of the lethal resonance. Realising what he means, Alice tells Jack to tell Dekker and Johnson no. Johnson warns that they're running out of time and Jack has no choice but to give the order. Alice runs screaming to her son.
The soldiers approach the abandoned buildings and Rhys and Gwen get everyone out the back. One child is left behind and tries to hide. The soldiers quickly find her.
Johnson's men grab Steven and restrain Alice when they try to stop them.
The soldiers close in on Gwen and the children.
Steven asks Jack what is happening as they place him in the centre of the resonance projector. Jack says nothing and continues to work.
The soldiers capture the children and restrain Rhys and Rhiannon. Gwen keeps running with one last child.
Jack stares at Steven for a moment and then activates the resonance projector. The boy starts screeching as Alice stares in horror. Children across the world emit the same sound. In Room 413, Oduya looks on as the 456 start to groan in agony. They smash against the walls and finally explode as the energy column withdraws into the sky above.
Jack, crying, watches as the resonance shakes his grandson apart.
Oduya finally informs Pierce that the 456 are gone.
Johnson finally lets Alice into the room. She runs to her son, lying dead on the platform, and holds her in the arms while begging anyone for help.
Pierce salutes the Prime Minister and leaves. Denise asks if he's ready to give a statement and he says that they were lucky. Pierce took control without UN ratification, so they can blame him for whatever happened. Bridget notes that his first concern is to save his own skin. She tells him that she went to see Lois and used the emergency protocols to sign out the Torchwood contact lenses. Lois explained to her how they worked. Bridget explains that she recorded everything that happened in the room and she'll make it all public. Green threatens to have her arrested but Denise thanks Bridget, tells her she's free to go, and promises to release Lois. She tells Green that she'll be taking charge of many things in the days to come and asks if that's all Green has to say. He can only stare in shock.
Alice comes out to look at Jack for a moment as he sits in the hallway, and then goes back inside. Jack remembers his grandson and then walks outside.
Six months later, Gwen and Rhys drive into the woods and come to the end of a dead-end road. They walk up a hill and find Jack waiting for them. Gwen asks if he's okay and he admits he is. Jack tells her that he's travelled across the world but it's too small for him and reminds him of a graveyard. She asks him to come back with them but he says he hasn't travelled enough yet. Jack explains that there's a cold-fusion cruiser on the edge of the solar system, and he needs to send a signal. Gwen gives him his wrist unit and asks if he'll ever come back. Jack wonders what there is to come back for and she says her. Gwen insists that it wasn't his fault but Jack says that all of the deaths were because of him, and it's time for him to find a new life. He signals the cruiser while Gwen insists he can't run away. He says he can and teleports away. As Gwen cries, Rhys tells her that it's time to go home.